The primary objectives of the biostatistics as core resource in the GI Cancer SPORE are proper design of studies, ongoing monitoring, ensuring data quality and completeness in ongoing studies, state-of-the-art statistical analyses of results, and assistance to investigators in interpreting and presenting result. The guiding philosophy will be to keep quantitative aspects of the research closely tied to the specific aims, and to have the collaboration of the investigator and biostatistician such that the biologic knowledge of the researcher plays an integral part in shaping the statistical analyses. To achieve these objectives, the core biostatistician will be available to SPORE investigators at all phases of their projects. Discussion of study aims, appropriate design parameters (i.e. study structure and sample size), interim analyses, analytical plans, interpretation of results and guidance for publication will be provided as needed. All analyses will use the most current methods and will be conducted or supervised by the statistician. Because many of these analyses are exploratory and are meant to assess new methods, there will be emphasis on estimation of important clinics and laboratory parameters with confidence intervals and likelihood/Bayesian methodology rather than statistical, hypothesis testing. The core statistician has experience in a number of areas of particular value to core investigators; inference in situations where there is relatively little empirical data, analysis of clinical research with small numbers of subjects, gene expression in GI tumors, and evaluation of cancer screening tests. He will be assisted by an experienced member of the Oncology/Biostatistics staff, who will have the responsibility for performing most of the statistical analyses under his supervision.